The invention relates to a system for wiping windshields, particularly with a spheroidal curvature, having a wiper arm system and a blade carrier holding device connected to the wiper arm system.
Numerous wiping arrangements have become known for motor vehicles. For example, European Patent Document EP-A-92201935.1 shows a wiping arrangement which comprises a wiper arm made of a composite material.
Nowadays, large-surface windshields are used not only in the automobile industry but also rail vehicles, particularly in the high-speed operation, as, for example, in the case of the ICE (Intercity Railroad) of the Deutsche Bahn AG (German Railroad Corporation). Such windshields provide the required large and good viewing area for the driver of the traction vehicle. In order to ensure such a viewing area of vision during poor visibility, for example, in rainy weather, it is necessary to provide windshield wiping systems whose overall wiper blade length is more than 600 mm, particularly up to 1,300 mm.
Special problems occur when the above-mentioned windshields are spheroidally curved and as the result of the high traveling speed in the operation. Thus, high traveling speeds require a particularly low air resistance. On the other hand, the arms of the wiper blade system must not lift off the windshield during the travel and must be securely held, particular in the parking position. In addition, the cost for the solution should be as low as possible.
It is an object of the invention to provide a wiping arrangement, particularly for rail vehicles in the high-speed operation, which solves the above-mentioned problems.
In particular, a system for wiping windshields is to be provided such that a large viewing area is obtained also under unfavorable weather conditions and a good wiping result is achieved even in the case of very curved, for example, spheroidally curved, windshields.
Furthermore, favorable aerodynamic conditions are to be obtained.
According to the invention, these objects are to be achieved in that the individual wiper arms of the wiping arrangement are constructed such that, in least in one position, preferably the inoperative or parking position, they are, in a substantial area of their longitudinal dimension, parallel to one another in a plane essentially perpendicular to the windshield plane. The angle of the plane with respect to the windshield surface is between 75 and 90. The wiper arms are therefore in the so-called biplane arrangement.
When in use, each of the individual wiper arms of the wiping arrangement, driven, for example, by an electric motor, carries out a rotating movement about a pivot assigned to the respective arm. The blade carrier holder or the blade carrier holding device also has two suspension points, one respectively for each arm, at which this arm is mounted, for example, by means of a bolt. As the result of the rotating movement of the wiper arms, the blade carrier holder and therefore the wiper blades also carry out corresponding movements.
It is therefore possible to clear a large viewing surface under poor weather conditions.
In order to obtain good results also in the case of spheroidally curved windshields, at least two wiper blades are arranged in parallel to and offset from each other on the blade carrier holder. In a further development, these may also be suspended in an oscillating manner on the blade carrier holding device. Furthermore, such an arrangement advantageously permits different radii of curvature for the individual blades, for example, of 2,000 mm and 3,000 mm. As the result of the use of wiper blades with different radii of curvature, a particularly good adaptation of the wiping arrangement to the curvature of the windshield can be achieved. The oscillating suspension also permits the wiping of very small radii of curvature of, for example, 2,000 mm, which has not been possible by the wiping arrangements known from the state of the art.
In order to obtain a smooth wiper blade movement in the case of different degrees of wetting on the windshield, a further development of the invention includes guiding devices for the individual wiper blades in the wiping arrangement.
In a further development of the invention, the individual wiper arms have an elliptical or curved profile. This can further reduce the air resistance of the arrangement.
For wiping a viewing area which is as large as possible and for ensuring a wiping of the lower field of viewing area without a collision of the windshield wiper ends with the windshield frame, the spacing of the linking points of the individual wiper arms on the blade carrier holding device is larger than the spacing of the pivots of the windshield wiper arms at the end on the other side of the wiper blades.
In order to permit a high stiffness of the wiper arms in the case of small profile crosssections, in an embodiment of the invention, the wiper arms are made of a fiber composite, preferably of carbon fibers. By using materials of this type, a low height of the wiper arms can be achieved so that the wiper arm height is still within the aerodynamic boundary layer and the air resistance can therefore be minimized.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.